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Homework Help: Calculate the linear acceleration of a car

  1. Oct 31, 2003 #1
    a) Calculate the linear acceleration of a car, the 0.300 m radius tires of which have an angular acceleration of 10 rad/sec^2, assume no slippage.

    a = ???
    r = 0.30 m
    Rot acc = 10.0 rad/s^2

    a = r * (rotational acc)
    a = .3 m * 10 rad/s^2
    a = 3.0 m/s^2

    b) How many revolutions do the tires make in 2.5 s if they start from a rest???

    V final = 10 rad/s^2 * 2.5 s * 1 rev / 2pie rad = 3.98 rev/s

    (Vf - Vo)/2 should give average velocity so

    (3.98 rev/s)/2 = 1.98 rev/s

    1.98 rev/s * 2.5 s = 4.97 rev

    c) What is their final angular velocity???

    W = Wo + (rotational acc) * time

    W = 10 rad/s^2 = 25 rad/s

    d) What is the final velocity of the car???

    v = (.3m) * (25 rad/s) = 7.5 m/s

    Could someone check this please - I feel relatively confident - but you will not hurt my feelings if you tell me I am wrong.

    Thanks
    Nautica
     
  2. jcsd
  3. Oct 31, 2003 #2

    jamesrc

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    Science Advisor
    Gold Member

    Your answers are correct. You could have done part b in one step if you used Δθ = ωo*t + .5*α*t^2 and there was a typo in the third line of your solution to part c, but that's neither here nor there.
     
  4. Nov 1, 2003 #3
    I see that now

    Thanks
    Nautica
     
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